In Debian we are currently applying the attached patch to Apache-Singleton.
We thought you might be interested in it, too.
From d63e6400c68fd8a0bcdf399d3e973f2cc708dabc Mon Sep 17 00:00:00 2001
From: Niko Tyni <ntyni@debian.org>
Date: Sun, 1 Apr 2012 21:35:56 +0300
Subject: [PATCH] Only use one Apache child process for testing
As seen in <http://bugs.debian.org/666601>,
t/apache/singleton/process/printer_instance.t occasionally
fails in a non-deterministic way. This happens when sequential GET
requests get served by different Apache child processes.
The tests clearly expect only one process serving the pages, so limit
MaxClients to one.
Thanks in advance,
gregor herrmann, Debian Perl Group